NFSv4.1: Fix bug only first CB_NOTIFY_LOCK is handled

commit ba851a39c9703f09684a541885ed176f8fb7c868 upstream.

When a waiter is waked by CB_NOTIFY_LOCK, it will retry
nfs4_proc_setlk(). The waiter may fail to nfs4_proc_setlk() and sleep
again. However, the waiter is already removed from clp->cl_lock_waitq
when handling CB_NOTIFY_LOCK in nfs4_wake_lock_waiter(). So any
subsequent CB_NOTIFY_LOCK won't wake this waiter anymore. We should
put the waiter back to clp->cl_lock_waitq before retrying.

Cc: stable@vger.kernel.org #4.9+
Signed-off-by: Yihao Wu <wuyihao@linux.alibaba.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index bef0e679a0d8d145edd1b243d1a3c509494bc0a1..eeee100785a5fc80c09294b46c91800ec30acb4f 100644 (file)
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -6922,20 +6922,22 @@ nfs4_retry_setlk(struct nfs4_state *state, int cmd, struct file_lock *request)
        init_wait(&wait);
        wait.private = &waiter;
        wait.func = nfs4_wake_lock_waiter;
-       add_wait_queue(q, &wait);
 
        while(!signalled()) {
+               add_wait_queue(q, &wait);
                status = nfs4_proc_setlk(state, cmd, request);
-               if ((status != -EAGAIN) || IS_SETLK(cmd))
+               if ((status != -EAGAIN) || IS_SETLK(cmd)) {
+                       finish_wait(q, &wait);
                        break;
+               }
 
                status = -ERESTARTSYS;
                freezer_do_not_count();
                wait_woken(&wait, TASK_INTERRUPTIBLE, NFS4_LOCK_MAXTIMEOUT);
                freezer_count();
+               finish_wait(q, &wait);
        }
 
-       finish_wait(q, &wait);
        return status;
 }
 #else /* !CONFIG_NFS_V4_1 */